This invention relates generally to hydrotherapy apparatus, such as spas and hot tubs, and, more particularly, to water-driven rotatable jets for use in such apparatus. Hydrotherapy pools, tubs, spas and baths have wall openings through which streams of water, or a water and air mixture, are discharged into a heated body of water. Persons seated or reclining in the water may position themselves appropriately to receive a therapeutic benefit from massage by the incoming water streams. Each stream enters through a fixture that will be referred to in this specification as a spa jet, although it will be understood that fixtures of the same type may be installed in bathtubs, hot tubs and other similar equipment.
Spa jets are typically made to be adjustable both in the direction in which the water is discharged, and in the rate of flow of the water. There may also be some control over the proportion of air in the water. Although fixtures of this general type have been in use for some years, it has only recently been recognized that additional therapeutic benefit may be obtained from a constantly moving stream of water. Various techniques have been proposed to achieve this end, but all have been unsatisfactory to some degree.
For example, U.S. Pat. No. 4,692,950 to Henkin et al. discloses apparatus in which a discharge jet is moved through a complex nonlinear and noncircular path to enhance the hydrotherapeutic properties. A jet nozzle is guided along a slot defining the complex path, and is propelled by a component of thrust developed as water is discharged through the nozzle.
U.S. Pat. No. 4,715,071, also issued Henkin et al., discloses another Version of the apparatus, in which a discharge jet follows a circular path. A conduit having a supply section, an intermediate section and a discharge section is mounted for rotation about the axis of the supply section. The discharge section is inclined at an acute angle to a plane through the supply and intermediate sections, resulting in a tangential thrust component that spins the conduit about the supply section axis. Unfortunately, the conduit is also subject to a radial thrust component, and must be mounted on cylindrical bearings to resist forces transverse to the axis of rotation. These bearings are subject to significant wear and may pose maintenance problems and limit the potential life of the fixture. Moreover, this technique does not permit adjustment of the speed of rotation, except by controlling the flow rate. Perhaps even more important as a practical matter is that the devices disclosed in these patents differ structurally from conventional spa jets, to such a degree that they could not be easily or conveniently installed in an existing spa or tub, nor could they be interchanged with other jets in the same spa or tub.
It will be appreciated from the foregoing that there is still a significant need for a spa jet assembly with water-driven rotational capability, but with additional features that render it more practical and useful. Ideally, a rotatable spa jet should be easily used to retrofit an existing installation having conventional spa jet nozzles, should have the ability to be adjusted in speed independently of the flow rate, and should be virtually maintenance free. The present invention meets these requirements and has additional advantages, as will become apparent from the following summary.